off-alarm (work in progress)

Purpose

off-alarm intends to monitor if a critical device has been inadverdently turned off and alert user using audible alarm. It monitors measurements from Tasmota nodes sending connected device power usage, light sensor readings, and a custom device that sends messages when a button is pressed and is able to play a tune on a piezo buzzer. These messages are sent over MQTT. off-alarm also queries InfluxDB that stores the previous light sensor and device power readings to determine whether an audible alarm should be played. Querying InfluxDB is only done when off-alarm first starts.

This project is for a very specific use case and a very specific hardware setup, and you may not find it useful as is, but there may be some useful snippets in the code if you are interested in building something similar.

Components

Server (ts running on bun): ./src

Web frontend (statically served by server): ./frontend

Device (ESP-IDF C code for ESP32): ./device-esp32

ESP32 Device

For more information on the device, see device-esp32/README.md.

Install (server)

To install dependencies:

bun install

Configure environment variables in .env file. Use .env.template as a template.

To run:

bun run dev

bun run prod

Runtime environment variables for debugging

Use fake sensor data

bunx cross-env USE_FAKE_SENSORS=Y bun run dev

Subscribes to fake sensor topics instead of topics that send real sensor data. Use with fakeSensorReadingEmittor.ts.

Emit fake sensor data

bun src/testSupport/fakeSensorReadingEmittor.ts

To make it emit illuminance sensor data where the room is dark:

bun src/testSupport/fakeSensorReadingEmittor.ts dark

To make it emit power use sensor data where the device is active:

bun src/testSupport/fakeSensorReadingEmittor.ts active

Enable verbose logging

bunx cross-env LOG_LEVEL=debug bun run dev

Sets log level to debug, the most verbose level. The default is info.

Persist sensor data (for debugging)

bunx cross-env PERSIST_SENSOR_DATA=Y bun run prod

Persists received sensor data to sensor.sqlite file.

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(C) 2025 Hoon Choi